IF Princess Diana had made it to 50, would she really have looked like Madonna after a night on the tiles?

And if Diana had not died at the age of 36, but celebrated her 50th birthday yesterday, would she really have clocked up multiple divorces like some blue-blooded Zsa Zsa Gabor?

Diana did not live long enough to get anywhere near those 50 candles. But her half-century had them queuing up to imagine what her life would look like if she had lived.

And everyone seemed to agree – Diana would be a train wreck.

The cover of Newsweek had her looking like an elderly vulture with an eating disorder. Inside the rag, the magazine imagined a decrepit Diana in 2011 – tweeting the Dalai Lama, brandishing an iPhone and smiling vacantly at some charity crowd.

I don’t buy it. None of it. For a start, I don’t think that Diana at 50 would have looked like Madonna after a lobotomy.

And I don’t believe she would have bounced from marriage to marriage like some fading soap star. And I certainly don’t believe she would have been tweeting Gwyneth Paltrow about their gym appointment.

I think that, had Diana lived, she would have found peace. I think she would have sought privacy. And, as she was one of those women who looks infinitely better at 35 than she did at 20, I think she would have looked great.

Healthy. Happy. And nothing like Madonna with constipation. We will never know.

But as Prince William and Kate embark on married life, I think we can say one thing with total conviction.